One option to increase capacity in a wireless network is to increase the density (number of devices per unit area) of deployed base stations or remote antenna units. If the density of the deployed base stations or remote antenna units increases, cell capacity increases due to frequency reuse effects. However, there are some difficulties that come with increasing the deployment density, especially if such deployed units must be able to operate as conventional base stations on their own. These difficulties include:                1) As the deployment density increases, the number of handovers increases because the user equipment changes its serving unit (base station) quite frequently. As a result, quality of connectivity/mobility is expected to be degraded. Thus, the deployed unit for increasing cellular capacity should have high-quality interworking with the macro base station.        2) The conventional macro base stations transmit some required signals, such as pilot signals, synchronization signals, broadcast signals, paging signals, and so on, all of which have the potential to cause interference problems. Such interference limits the number of deployed base stations and thus lowers cellular capacity.        3) Furthermore, radio resources for the required conventional macro base station signals are typically static. Thus, dynamic and efficient interference coordination through dynamic allocation of the radio resources is difficult, which also limits the number of the deployed base stations and associated cellular capacity.        4) Network operators need to assign cell ID or other cell-specific parameter to each cell. For example, the root sequences for random access channels in LTE uplink (UL) are an example of such cell-specific parameters. Such cell planning for the cell ID, the root sequences and the like is cumbersome, which also limits the number of the deployed base stations and associated cellular density.        5) The required cell capacity is region-specific. For example, a significantly large capacity is required in urban areas whereas a relatively small enhancement of cell capacity may be sufficient in suburban or rural areas. To efficiently satisfy such divergent density needs, the deployed unit should be easily installed with low cost/complexity        6) If the cost of each deployed unit is high, the total system cost is quite high as the deployment density increases. Thus, the deployed unit cost should be relatively low to feasibly increase cell capacity.        
Various architectures have thus been proposed to increase wireless network capacity. For example, distributed base stations using the Remote Radio Head (RRH) technology communicate with a base station server using optical fiber. Because the base station server performs the baseband processing, each RRH distributed base station thus acts as a power amplifier with regard to its base station server. As the density of the RRH distributed base stations is increased, the baseband processing complexity is increased at the base station server. Thus, the number of RRH cells corresponding to each distributed RRH base stations is limited due to this baseband complexity.
Another alternative for increasing wireless network capacity involves the use of picocells or femtocells. Unlike the RRH approach, baseband processing is distributed across the pico/femtocells. But there is no high-quality interworking between picocells/femto cells and macrocell base stations. Thus, connectivity and mobility may not be sufficient because conventional intra-frequency or inter-frequency handover between picocells/femtocells and macrocell base stations is required. Furthermore, the picocells/femtocells are indeed base stations and thus they transmit the signals mentioned above such as pilot signals, synchronization signals, broadcast signals, paging signals, and so on. As a result, as the deployment density for pico/femtocells is increased, interference problems, difficulties in dynamic and efficient interference coordination, cell planning problems, and related issues cannot be solved.
Yet another alternative for increasing wireless network capacity is the use of conventional WiFi. But there is no interworking between WiFi nodes and macrocell base stations. Thus, connectivity and mobility is limited for a dual macrocell and WiFi user. Moreover, the use of WiFi in macrocell networks introduces the complications of multiple IP addresses being assigned to a single user.
Accordingly, there is a need in the art for improved architectures and techniques for increasing wireless network capacity.